Kusari-Gama

Kusarigama at Iwakuni Castle
The kusarigama (lit. “chain-sickle”) is a traditional Japanese weapon that consists of a kama (the Japanese equivalent of a sickle) on a kusari-fundo – a type of metal chain (kusari) with a heavy iron weight (fundo) at the end. The kusarigama is said to have developed during the Muromachi period.The art of handling the kusarigama is called kusarigamajutsu.
Attacking with the weapon usually entailed swinging the weighted chain in a large circle over one’s head, and then whipping it forward to entangle an opponent’s spear, sword, or other weapon, or immobilizing his arms or legs. This allows the kusarigama user to easily rush forward and strike with the sickle.

A kusarigama wielder might also strike with the spinning weighted end of the chain directly while still outside the range of an opponent’s hand weapon.